Energy-efficient trenching tool

The hardened-steel Rolling Wedge Cutter pulls rather than blasts asphalt and concrete apart. Besides being less damaging to ground beneath streets and roads than backhoes and jackhammers forcing their way through pavement, the process uses 60% to 70% less energy. Diameters: 0.75 to 9 in. Philippi-Hagenbuch Inc. www.philsystems.com